A Redundant Array of Independent, or Inexpensive, Disks (RAID) is a collection of two or more storage disks for storing machine readable data. Typically, the disks operatively function under the control of a controller that manages the processes relating to information storage and retrieval on the disks.
In a conventional computing environment, an RAID is utilized for the sharing or replicating of data among multiple disk drives. The RAID provides a mechanism for storing the same data in different places—that is, redundantly—on multiple hard disks. The arrangement is intended to place data on multiple disks, such that input/output operations can overlap one another in a balanced way, thereby improving performance. Moreover, because multiple disks increase the mean-time-between-failure (MTBF), storing data redundantly increases fault-tolerance. Accordingly, the benefits often associated with the RAID include enhanced data integrity, fault-tolerance and/or performance relative to computing device that use a single disk drive. An initial impetus for the RAID was to combine multiple low-cost devices using older technology so as to achieve such advantages.
Notwithstanding these acknowledged advantages afforded by the RAID, some limitations remain with respect to the power consumption of such a device. Newer systems and devices that utilize the RAID—including not just laptop computers, for example, but other devices such as data communication network servers—tend to consume more power in effecting input-output (I/O) operations.
Energy consumption of disk drives used in web servers, for example, accounts for as much as 24% of the servers' total power usage. In proxy servers, that energy consumption can be as high as 77% of the total usage. As newer, more sophisticated devices evolve, the concern over energy costs associated with disk drives is likely to intensify. Thus, there is a need in the art for a way to reduce the amount of power consumed by a conventional RAID without degrading performance or sacrificing the reliability that was an original objective of such a device.